<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript">
		
			var n1=10;
			var n2=20;
			
			var n = n1++; //n1 = 11  n1++ = 10
			
			console.log('n='+n);  // 10
			console.log('n1='+n1); //11
			
			//n = 10. n1 = 11
			n = ++n1 // n = 12, n1 = 12
			console.log('n='+n); //12
			console.log('n1='+n1); //12
			
			//n = 12, n2 = 20
			n = n2--;// n = 20, n2 = 19
			console.log('n='+n); //20
			console.log('n2='+n2); //19
			
			// n = 20, n2 = 19
			n = --n2; // n = 18, n2 = 18
			console.log('n='+n); //18
			console.log('n2='+n2); //18
			
			
		</script>
	</head>
	<body>
	</body>
</html>
